In the course of researches mafic-ultramafic vulkano-plutonic association of Vetreny Poyas paleorift samples from different rocks have been selected for zircon allocation for U-Pb isotopic researches and for the purpose of age definition of Myandukha komatiitic basalts. Zircon, allocated from selected in 2003 from komatiitic basalts, have been analysed in VSEGEI by V.F.Smolkin (Smolkin, Spheres, 2009). Zircon from other objects also were studied: massif of Rujga, Vyzhiga, and lava lake cumulates of B.Levgora.
Zircon grains are met both near to the basis of streams, in drills of intrusions close boundaries and without special positions in dykes. They possess sometimes well remained crystallographic forms, but represent resorbed crystals or more often their fragments. Crystals are zoned. It is caused not only the sizes and uniformity degree of the zones, but also their variable structure. Zircon has obvious «non syngenetic» character in an researched rock complex. They are divided into: 1) xenogenic, grasped by lava (Sinegore) and concentrated in a bottom part of covers or in a roofing part of intrusions (except of Vyzhiga massif, where they are dated for a bottom); 2) secondary in baddeleites in the form of an external cover which tends to replace them almost completely.